Today, as a power supply device configured to convert an alternate-current voltage into a direct current voltage, switching power supply devices having excellent characteristics in miniaturization, weight reduction, and efficiency are widely used. Such a switching power supply device first converts an alternate-current voltage into a direct current voltage, and thereafter raises or lowers the voltage so as to reach the voltage required for driving a load.
With respect to such a switching power supply device, various techniques have been developed in order to propel stabilization of an output voltage, improvement in efficiency, miniaturization and the like (see, for example, Patent Literature 1).